Aerodynamic forces applied to a wing of an aircraft cause the wing to primarily bend vertically and twist forward in flight. In a large jetliner, these wing bending deflections can induce undesirable loads in the fuselage, creating challenges in achieving efficient designs where the wing and fuselage are joined together (the “wing-to-body connection”). These forces act on the fuselage, primarily in the aircraft vertical, lateral, and axial directions. Further, the vertical force creates a bending moment. Additional fuselage loads at the wing-to-body connection are produced by changes in pressure within the fuselage.
A “rigid” wing-to-body connection may be designed to transfer all wing bending deflections to the fuselage components at the connection interface. As a result, these designs cause fuselage components to rotate and bend in unison with the wing. A “compliant” wing-to-body connection may instead be designed to transfer vertical, lateral and axial loads without transferring wing bending deflections such that the wing can bend independently of the fuselage.
Compliant designs have historically used a few isolated complex mechanical linkages and/or pins. However, these designs require heavy wing and fuselage structure to support large loads which concentrate at the few discrete wing-to-body connection locations.
These heavy structures add weight to the aircraft. The added weight increases fuel consumption and other aircraft operating costs.